The forbiden word is Fully Synthetic or Vollsynthetisches öl, that is exclusive for GTL or PAO oil. Group III are always labeled as HC Synthetic or Synthetic in Europe, not just Germany. Big brands like Castrol, Mobil, Aral, Total, Shell, Adinol, Fuchs, Liquimoly, Motul, etc. follow this rule.
Gen III or hydrocracked base is not synthethized, it is from mineral oil that is saturated with Hydrogen to make it more stable in addition to chopping longer carbon chains. The quality depends on the source of the mineral base oil itself. I emailed the Oil maker directly and ask if their oil is group III or group IV, they usually answered and saying group III or semisynthetic.
The GTL and PAO are made from smaller building blocks, like LEGO, the opposite of Hydrocracked process. However, at the end for us is about the effective performance. Most group III oil perform almost as good as group IV and GTL with the right formulations and additives.
From Virgin oil analysis, GTL oil (Shell/Pennzoil Ultra Platinum) needs less additives than non GTL version. Base oil is more stable than additives.